Commodus is the spoiled, royal son of Emperor Marcus Aurelius. Commodus does not arrive on the Germanic fontier until after all the fighting is over. Marcus Aurelius disapproves of his son and blames himself for how Commodus turned out. Marcus tells Commodus that he intends to name Maximus as his heir. Commodus is stunned and then enraged. He smothers his father, so that he can become Emperor of Rome.

Commodus has a natural jealousy and competitiveness with Maximus. Maximus has earned his father's approval and acceptance as a 'better son' than Commodus. Maximus has also been a past lover of Commodus' sister, Lucilla. Even now, she still carries a flame for Maximus who is now married. This love also bothers Commodus, since he has a rather incentuous desire for his own sister.

In order to secure his place on the throne, Commodus orders Maximus killed when Maximus refuses to swear allegience to his new emperor. Commodus also orders Maximus' family killed. Commodus then returns to Rome like a conquering victor even though he had not commanded at any military victories. He quickly intimidates much of the Roman Senate. In order to win over the populus of Rome, he reinstates the gladiatorial games in the Coliseum.

All is going well until an anonymous gladiator defies Emperor Commodus' order of death to a defeated gladiator and has the crowd's support in his defiance. Commodus soon finds out that the gladiator is Maximus. Now, Commodus is concerned since Maximus the gladiator has the support of the populus, but also as a former general just might have the means to threaten his polical power as well. His sister Lucilla and Senator Gracchus attempt to use Maximus in a plot to remove Commodus from power, but he discovers their plot. He arrests Gracchus, threatens his sister with harm to his nephew Lucius and sets up Maximus. After giving Maximus a fatal knife wound, he fights Maximus in the Coliseum before the people of Rome. In spite of the unseen wound, Maximus defeats and kills Commodus.